Operating microscope

ABSTRACT

An operating microscope having an image projecting optical system ( 9 ) for introducing an image derived from an endoscopic optical system, which is provided separate from an operating-microscopic optical system, into an eyepiece optical system ( 18 ) of the operating microscope so that the operating-microscopic image and the endoscopic image can be simultaneously observed. The image projecting optical system ( 9 ) includes a collimating optical system ( 10 ), which collimates a beam of rays emergent from the image derived from the endoscopic optical system, and an imaging optical system ( 13 ), which forms an image on an image surface of the operating-microscopic optical system provided for observation via eyepiece using the beam of parallel rays emergent from the collimating optical system ( 10 ). The imaging optical system ( 13 ) is constructed to be movable at least in such a range that its entrance aperture can receive the beam of parallel rays. Whereby, the operating-microscopic image and the endoscopic images are simultaneously observed via the eyepiece optical system ( 18 ) of the operating microscope irrespective of adjustment of interpupillary distance, and the operating microscope is constructed to be compact and highly operable.

This application is a Div. of Ser. No. 09/053,620 filed Apr. 2, 1998,U.S. Pat. No. 6,088,154.

BACKGROUND OF THE INVENTION

a) Field of the Invention

This invention relates to an operating microscope, specifically to thatincorporating an endoscopic image into an operating-microscopic image toallow simultaneous observation.

b) Description of the Related Art

For surgical treatment in cerebral neurosurgery, otorhinolaryngology,ophthalmology or other clinical specialty, operating microscopes haveplayed such an important role as to improve efficiency of surgicaloperations by providing observers with enlarged images of partssubjected to the operations. Furthermore, in recent years, endoscopicobservation also is applied to the operations that used to be performedonly under the operating-microscopic observation, so that tissues otherthan the minimum necessary portions for the operation remain intact; itis preferred that the operating-microscopic image and the endoscopicimage can be observed simultaneously.

A microscope apparatus disclosed by Japanese Patent ApplicationLaid-Open Number Sho 62-166310, for example, is known to be directed tothe combination of the operating microscope and the endoscope. In thisapparatus, an endoscope with a solid-state image pickup device forstereoscopic observation is provided to be movable with respect to astereoscopic microscope so as to allow observation inside a narrowcavity, which were impossible otherwise. Moreover, the apparatusincludes an image reproducing means for displaying the image derivedfrom the solid-state image pickup device and an image projecting meansfor introducing the image displayed on the image reproducing means intoan eyepiece optical system so that the eyepiece optical system iscommonly used for simultaneous observation of the operating-microscopicimage and the endoscopic image.

However, the art of the Japanese Patent Application Laid-Open Number Sho62-166310 fails to consider the problem caused by the shift of the imagesurfaces which are provided for observation via eyepiece, which shiftaccompanies adjustment of interpupillary distance, and thus cannot bereduced into realization for a practical operating microscope.

The adjustment of interpupillary distance is performed by shifting theleft and right sections of the operating microscope, in each of which animage surface is provided for observation via eyepiece, so that thedistance between the left and right eyepoints of the operatingmicroscope corresponds to the distance between the left and right pupilsof an observer. Every operating microscope is provided with a mechanismto perform this adjustment. If the interpupillary distance is to beadjusted in practice using only the art known from the above-mentionedSho 62-166310, it is necessary to shift the image reproducing meansthrough the image projecting means integral with the shift of the imagesurfaces provided for observation via eyepiece so that the positions onwhich the images from the image reproducing means are projected followmovement of the eyepiece optical system resulting from the adjustment ofinterpupillary distance. This configuration requires a space formovement of optical system or elements inside a housing of the operatingmicroscope, to render the housing voluminous. As a result, according tothe art of the above-mentioned Sho 62-166310, it is impossible to makean operating microscope compact in its entirety, while the operatingmicroscope is fundamentally required to be made compact for efficiencyof the surgical work.

SUMMARY OF THE INVENTION

The present invention is made considering the above-mentioned problem ofthe conventional art. An object of the present invention is to providean operating microscope in which the operating-microscopic image and theendoscopic image can be constantly and simultaneously observed via theeyepiece optical system irrespective of adjustment of interpupillarydistance by causing images obtained from an endoscopic optical system tobe projected as to follow the shift of the image surfaces of theoperating-microscopic optical system resulting from the adjustment ofinterpupillary distance, and which is also made compact to facilitatethe surgical work.

In order to attain the above-mentioned object, according to the presentinvention, an operating microscope comprising an image projectingoptical system for introducing an image derived from an endoscopicoptical system, which is provided separate from an operating-microscopicoptical system, into an eyepiece optical system of the operatingmicroscope so that the operating-microscopic image and the endoscopicimage can be simultaneously observed is characterized; in that the imageprojecting optical system includes a collimating optical system, whichcollimates a beam of rays emergent from the image derived from theendoscopic optical system, and an imaging optical system, which forms animage on an image surface of the operating-microscopic optical systemprovided for observation via eyepiece using the beam of parallel raysemergent from the collimating optical system; and in that the imagingoptical system is constructed to be movable at least in such a rangethat its entrance aperture can receive the beam of parallel rays.

According to this configuration, an image by the endoscopic opticalsystem can be projected on the image surface as to follow the same,which is constructed to be movable for adjustment of interpupillarydistance. Therefore, the observer can observe the operating-microscopicimage and the endoscopic image constantly and simultaneously,irrespective of the adjustment of interpupillary distance.

Furthermore, since the collimating optical system is fixedly placedduring the adjustment of interpupillary distance of the operatingmicroscope, a space for moving the collimating optical system therein isnot necessary in a housing of the operating microscope, which featurefacilitates compact design of the operating microscope.

Furthermore, the image projecting optical system and theoperating-microscopic optical system are provided independent of eachother, without any common constituent optical element. Therefore, theseoptical systems do not degrade images formed by each other, and thusboth the images can be viewed clearly.

Also, according to the present invention, an operating microscopecomprising an image projecting optical system for introducing imagesderived from an endoscopic optical system, which is provided separatefrom an operating-microscopic optical system, into an eyepiece opticalsystem of the operating microscope so that the operating-microscopicimage and the endoscopic image can be simultaneously observed ischaracterized; in that the image projecting optical system includes acollimating optical system, which collimates a beam of rays emergentfrom the image by the endoscopic optical system, and an imaging opticalsystem, which forms an image onto an image surface of theoperating-microscopic optical system using the beam of parallel raysemergent from the collimating optical system; and in that an opticalaxis of the imaging optical system aligned with the beam of parallelrays is parallel to a direction in which the eyepiece optical system,onto which the image by the endoscopic optical system is projected,slides for adjustment of interpupillary distance as well as the imagingoptical system is constructed to be movable along the optical axis insuch a range that its entrance aperture can receive the beam of parallelrays.

The image projecting optical system of this configuration is preferablyapplicable to an operating microscope provided with a Jentzsche systemfor adjustment of interpupillary distance. According to thisconfiguration, an image by the endoscopic optical system can beprojected on the image surface as to follow the same, which isconstructed to be slidable for the adjustment of interpupillarydistance. Therefore, the observer can observe the operating-microscopicimage and the endoscopic image constantly and simultaneously,irrespective of the adjustment of interpupillary distance.

Furthermore, since the collimating optical system is fixedly placedduring the adjustment of interpupillary distance of the operatingmicroscope, a space for moving the collimating optical system therein isnot necessary in a housing of the operating microscope, which featurefacilitates compact design of the operating microscope.

Furthermore, the image projecting optical system and theoperating-microscopic optical system are provided independent of eachother, without any common constituent optical element. Therefore, theseoptical systems do not degrade images formed by each other, and thusboth the images can be viewed clearly.

Also, according to the present invention, an operating microscopecomprising an image projecting optical system for introducing an imagederived from an endoscopic optical system, which is provided separatefrom an operating-microscopic optical system, into an eyepiece opticalsystem of the operating microscope so that the operating-microscopicimage and the endoscopic image can be simultaneously observed ischaracterized; in that the image projecting optical system includes acollimating optical system, which collimates a beam of rays emergentfrom the image by the endoscopic optical system, and an imaging opticalsystem, which forms an image onto am image surface of theoperating-microscopic optical system using the beam of parallel raysemergent from the collimating optical system; and in that an opticalaxis of the imaging optical system aligned with the beam of parallelrays is perpendicular to a direction in which the eyepiece opticalsystem, onto which the image by the endoscopic optical system isprojected, slides for adjustment of interpupillary distance as well asthe imaging optical system is constructed to be movable in a planeperpendicular to the beam of parallel rays in such a range that itsentrance aperture can receive the beam of parallel rays.

The image projecting optical system of this configuration is preferablyapplicable to an operating microscope provided with a Siedentoph systemfor adjustment of interpupillary distance. According to thisconfiguration, an image by the endoscopic optical system can beprojected on the image surface as to follow the same, which isconstructed to be slidable for the adjustment of interpupillarydistance. Therefore, the observer can observe the operating-microscopicimage and the endoscopic image constantly and simultaneously,irrespective of the adjustment of interpupillary distance.

Furthermore, since the collimating optical system is fixedly placedduring the adjustment of interpupillary distance of the operatingmicroscope, a space for moving the collimating optical system therein isnot necessary in a housing of the operating microscope, which featurefacilitates compact design of the operating microscope.

Furthermore, the image projecting optical system and theoperating-microscopic optical system are provided independent of eachother, without any common constituent optical element. Therefore, theseoptical systems do not degrade images formed by each other, and thusboth the images can be viewed clearly.

Also, according to the present invention, an operating microscopecomprising an image projecting optical system for introducing an imagederived from an endoscopic optical system, which is provided separatefrom an operating-microscopic optical system, into an eyepiece opticalsystem of the operating microscope so that the operating-microscopicimage and the endoscopic image can be simultaneously observed ischaracterized in that at least one pair of trapezoidal prisms arearranged in mirror symmetry in a binocular optical system of the entireoperating-microscopic optical system to act as path deflecting means byreflecting rays three times inside themselves.

In order to achieve compact design of an operating microscope providedwith an image projecting optical system, not only the image projectingoptical system but also the operating-microscopic optical system arerequired to be compact. The above-mentioned configuration using thethree-times reflection prisms is advantageous for its compactness inthickness direction over a configuration in which trapezoidal prisms arearranged to reflect rays twice inside themselves as the path deflectingmeans (FIG. 20A) Therefore, the above-mentioned configuration of thepresent invention is capable of providing an operating microscope thatis small in size but allows simultaneous observation ofoperating-microscopic image and endoscopic image, by reducing thicknessof the binocular optical system of the entire operating-microscopicoptical system, which is to be juxtaposed with the image projectingoptical system.

In describing the invention, the present inventor often uses the terms“Jentzsche” and “Siedentoph” to divide adjustment systems forinterpupillary distance into two types. This classification is made notby the structure of the adjustment device but by how the binoculareyepiece moves. Those adjusting interpupillary distance by shifting theleft and right eyepieces linearly along a single line are referred to asJentzsche type system, while those adjusting interpupillary distance bymoving the left and right eyepieces along an arcuate locus are referredto as Siedentoph type system.

This and other objects as well as the features and advantages of thepresent invention will become apparent from the following detaileddescription of the preferred embodiments when taken in conjunction withthe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a right-side sectional view of optical systems in a binocularsection of the operating microscope according to the first embodiment ofthe present invention, for showing the overall configuration of theoptical systems;

FIG. 2 is an explanatory view illustrating the eyepiece optical systemshown in FIG. 1;

FIG. 3A is a view for explaining the optical principle of the firstembodiment shown in FIG. 1, illustrating a condition where an imagingoptical system is disposed in the center axis of a beam of parallelrays;

FIG. 3B is a view for explaining the optical principle of the firstembodiment, illustrating a condition where the imaging optical system isshifted from the center axis in a plane perpendicular to the beam ofparallel rays;

FIG. 4 is an explanatory view illustrating how rays are reflected byprisms and mirrors of an image projecting optical system used in thefirst embodiment;

FIG. 5 is a schematic view showing an application where an endoscopeprovided with a CCD cooperates with the operating microscope illustratedin FIGS. 1 through 4;

FIG. 6 shows an image obtained through the right eyepiece of theoperating microscope according to the first embodiment;

FIG. 7 is a side view of optical systems in the binocular section of theoperating microscope according to the first embodiment, which isprovided with a Siedentoph system for adjustment of interpupillarydistance, selectively showing the movable units for interpupillaryadjustment including the parallelogram prism, the eyepiece opticalsystem and the image projecting optical system, to detail theirconfiguration;

FIG. 8 is a front view of optical arrangement around the eyepieceoptical system and the image projecting optical system according to thesecond embodiment of the present invention;

FIG. 9 is a plan view of the optical arrangement around the eyepieceoptical system and the image projecting optical system according to thesecond embodiment of the present invention;

FIG. 10 shows the binocular optical system of the entireoperating-microscopic optical system according to the second embodiment,to explain that this embodiment employs Jentzsche method for adjustinginterpupillary distance of the binocular eyepiece;

FIG. 11A is a view for explaining the optical principle of the secondembodiment shown in FIG. 9, illustrating a condition where the imagingoptical system is disposed in the normal position;

FIG. 11B is a view for explaining the optical principle of the secondembodiment, illustrating a condition where the imaging optical system isshifted along the optical axis;

FIG. 12 shows right and left images for observation via binoculareyepiece according to the second embodiment, where images by the imageprojecting optical system are incorporated;

FIG. 13 illustrates in detail an image projecting optical system used inthe first and second embodiments;

FIG. 14 illustrates in detail another image projecting optical system(compatible with high-image-quality LCD) alternatively used in the firstand second embodiments;

FIG. 15 is directed to the third embodiment of the present invention,showing that a light intercepting member is disposed in the movablesection of such an image projecting optical system as used in the firstor second embodiment;

FIG. 16 is directed to the fourth embodiment of the present invention,showing that a movable prism is arranged in the movable section of suchan image projecting optical system as used in the first or secondembodiment;

FIG. 17 is directed to the fifth embodiment of the present invention,showing that a binocular optical system inclusive of left and righteyepiece optical systems, an image projecting optical system, and acompact LCD are housed in a binocular housing similar to that used inthe first or second embodiment to form an integral binocular unit, whichis constructed to be removably mounted on the main housing of theoperating microscope;

FIG. 18 is directed to the sixth embodiment of the present invention,showing that a binocular section of the operating microscope similar tothat used in the first or second embodiment is constructed to havevariable inclination angle, and that the image projecting optical systemis built in a movable housing;

FIG. 19 is directed to the seventh embodiment of the present invention;

FIG. 20A is a plan view directed to the eighth embodiment of the presentinvention, showing arrangement of the binocular optical system of theentire operating-microscopic optical system, where Siedentoph system isincorporated to adjust interpupillary distance;

FIG. 20B is a side view of FIG. 20A;

FIG. 21A is a plan view directed to the eighth embodiment of the presentinvention, showing arrangement of the binocular optical system of theentire operating-microscopic optical system, where Jentzsche system isincorporated to adjust interpupillary distance;

FIG. 21B is a side view of FIG. 21A;

FIG. 22A illustrates how rays are reflected by a trapezoidal prism ofone example that is applicable to the binocular optical system;

FIG. 22B illustrates how rays are reflected by a trapezoidal prism usedin the binocular optical system according to the eighth embodiment;

FIG. 23 illustrates pupil arrangement in detail about the eyepieceoptical system according to the ninth embodiment of the presentinvention;

FIG. 24A shows optical arrangement according to the tenth embodiment ofthe present invention;

FIG. 24B is a perspective view of the compact LCD used in the tenthembodiment;

FIG. 25A is an overview of a binocular unit according to the eleventhembodiment of the present invention;

FIG. 25B is a cross-sectional view of the binocular unit shown in FIG.25A;

FIG. 26 shows optical arrangement according to the twelfth embodiment ofthe present invention;

FIG. 27A is a schematic view showing the overall configuration of thethirteenth embodiment of the present invention;

FIG. 27B shows optical systems in the binocular section according to thethirteenth embodiment; and

FIG. 28 shows optical systems in a binocular section according to thefourteenth embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

First Embodiment

In reference to FIGS. 1 and 2, description will be made of theconfiguration of optical systems in the binocular section of anoperating microscope according to the first embodiment of the presentinvention.

As shown in FIG. 1, optical components housed in a binocular housing 5is roughly divided into a binocular optical system 6 of the entireoperating-microscopic optical system and an image projecting opticalsystem 9 for introducing light emergent from a compact LCD 7 into aright image surface 8 of the binocular optical system 6.

Although FIG. 1 shows only the right-side optical members of thebinocular optical system 6, the first embodiment is provided withleft-side optical members of identical structure as a matter of course.The binocular optical system 6 of the entire operating-microscopicoptical system includes, on each of left and right sides, an imagingoptical system 20, an image rotator I, a parallelogram prism 1, an imagesurface 8 provided for observation via eyepiece, and an eyepiece opticalsystem 18. The binocular optical system 6 employs Siedentoph method foradjusting interpupillary distance; as illustrated in FIG. 2, theparallelogram prisms 1 pivot on center axes 2 of beams of rays incidentthereon integral with the respective eyepiece optical systems 3 disposedon the exit side thereof so as to adjust distance “a” between left andright eyepoints 4.

The image projecting optical system 9 includes a compact LCD 7 on whichan electronic image is displayed, a mirror 11, a collimating opticalsystem 10 for collimating a beam of rays emergent from the LCD 7, aprism 12, an imaging optical system 13 for forming an image onto theright image surface 8 using a beam of parallel rays emergent from thecollimating optical system 10, and prisms 14 and 15. The collimatingoptical system 10, the compact LCD 7, the mirror 11, and the prism 12constitute a fixed section 16, which remains stationary during theadjustment of interpupillary distance of the binocular eyepiece, whilethe imaging optical system 13 and prisms 14 and 15 constitute a movablesection 17, which moves integral with the right image surface 8 inaccordance with the adjustment of interpupillary distance of thebinocular eyepiece of the operating microscope.

The light beam travelling between the fixed section 16 and the movablesection 17 in the image projecting optical system 9 is constructed ofparallel rays. Therefore, even if the movable section 17 shifts inaccordance with the adjustment of interpupillary distance of thebinocular eyepiece of the operating microscope, the electronic imagefrom the compact LCD 7 can always be projected onto the image surface 8as long as the shift is made within such a range as allows the entranceaperture of the movable section 17 to receive the beam of parallel rays.Accordingly, the observer, whose pupil 19 is set behind the eyepieceoptical system 18, can view the electronic image from the compact LCD 7inside an observation field formed by the right eyepiece optical system18 of the operating-microscopic optical system.

Next, the optical principle relating to the image projecting opticalsystem with the above-mentioned configuration of the first embodimentwill be described in reference to FIGS. 3A and 3B. According to FIGS. 3Aand 3B, the compact LCD is represented by the reference numeral 21, thebeam of rays emergent from the compact LCD 21 by the reference numeral22, the fixed section of the image projecting optical system by thereference numeral 23, the collimating optical system by the referencenumeral 24, the beam of parallel rays by the reference numeral 25, themovable section of the image projecting optical system by the referencenumeral 26, the center axis of the beam of parallel rays 25 by thereference numeral 27, the image surface provided for observation viaeyepiece by the reference numeral 28, and the imaging optical system bythe reference numeral 29.

As shown in FIG. 3A, the beam of rays 22 emergent from the compact LCD22 is transmitted through the collimating optical system 24 to becomethe beam of parallel rays 25. Since each of optical elementsconstituting the fixed section 23 has such a large diameter as to coverthe moving range of the movable section 26, the beam of parallel rays 25with a large breadth (diameter) “b” also covers the moving range of themovable section 26. As a result, as shown in FIG. 3B, the imagingoptical system 29 can always receive the beam from the compact LCD 21 inthe constant condition even if it shifts along a plane perpendicular tothe center axis 27 of the beam of parallel rays 25. Furthermore, sincethe image surface 28 shifts integral with the imaging optical system 29,the imaging optical system 29 constantly forms an image derived from theelectronic image on a predetermined position on the image surface 28.

Next, in reference to FIG. 4, it will be explained how a beam of lightrays is reflected by prisms and mirrors of the image projecting opticalsystem used in the first embodiment. According to FIG. 4, the prisms arerepresented by the reference numerals 30 and 31, the image surfaceprovided for observation via eyepiece by the reference numeral 32, thecenter axis of the beam of rays incident on the parallelogram prism 1 bythe reference numeral 33, the compact LCD by the reference numeral 34,and a projected image by the reference numeral 35.

As shown in FIG. 4, the two prisms 30 and 31 included in the movablesection of the image projecting optical system 9 are so arranged as todirect the beam emergent from the fixed section of the image projectingoptical system 9 toward the image surface 32 by reflecting it twicewithout changing travelling direction of the beam. According to thisconfiguration, even if the movable section of the image projectingoptical system 9 pivots on the center axis 33 of the beam incident onthe parallelogram prism 1 integral with the parallelogram prism 1, theprojected image 35 derived from the electronic image on the compact LCD34 do not rotate; the electronic image displayed on the compact LCD 34is constantly projected in its proper attitude onto the image surface32.

Next, description will be made of an application where the operatingmicroscope with the above-mentioned structure is used with an endoscopeprovided with CCD in reference to FIG. 5. According to this application,an endoscope 37 with a CCD, a camera control unit 41, a light sourceunit 42 for the endoscope 37, a CCD camera adapter 43 for endoscopes, abinocular section 48 of the operating microscope, a main section 49 ofthe operating microscope, a light source unit 44 for the operatingmicroscope, light guides 46 and 47, and a cable 45 are interconnected asschematically shown in FIG. 5.

As shown in FIG. 5, the endoscope 37 with a CCD cooperates with theoperating microscope so as to facilitate observation of a narrow cavityinterior 36 located in parts 51 under operation, which is not observableby the operating microscope alone. If an electronic image picked up bythe endoscope 37 is displayed on the compact LCD 34 (FIG. 4) of theimage projecting optical system 9 (FIGS. 1, 3 and 4), this electronicimage displayed on the compact LCD 34 also is projected onto the rightimage surface as to follow the same, which is constructed to be movablefor adjustment of interpupillary distance of the binocular section 48,and thereby an observer 50 can observe an operating-microscopic image 39and an endoscopic image 40 simultaneously within an observation field 38formed by the right eyepiece optical system.

In addition, according to the first embodiment, since the compact LCD 7,the collimating optical system 10, the mirror 11 and the prism 12, whichoccupy a considerable space in the binocular housing 5, are fixedlypositioned as shown in FIG. 1, the housing 5 is not required to providean extra space for their movement and accordingly, a compact operatingmicroscope with high operability is realized while achieving theabove-mentioned advantage, i.e. simultaneous observation of theoperating-microscopic image and the endoscopic image.

Next, in reference to FIG. 6, description will be made of the imageprovided for observation via right eyepiece of the operating microscopeaccording to the first embodiment. According to FIG. 6, the observationfield formed by eyepiece of the operating microscope is represented bythe reference numeral 52, the operating-microscopic image by thereference numeral 55, and the endoscopic image by the reference numeral56.

The image projecting optical system 9 (FIGS. 1, 3 and 4) of the firstembodiment projects the electronic image displayed on the compact LCD 34(FIG. 4) onto the right image surface 8 (FIG. 1) so that the endoscopicimage 56 is located at a peripheral portion 53 in the upper-rightquadrant of the observation field 52. As a result, the vicinity of afield center 54 of the observation field 52 of the microscope isreserved for the operating-microscopic image 55.

According to this configuration, observation of theoperating-microscopic image 55, which is the principal image, iscompatible with observation of the endoscopic image 56, which serves asan auxiliary image. On the other hand, since an object located in thevicinity of the field center 54 is used as a target to be in focus by anauto-focusing device, it is necessary in using a microscope withauto-focusing function that the vicinity of the field center 54 isoccupied by the operating-microscopic image 55. The image arrangement inthe observation field according to the first embodiment is preferablealso in that it would not affect auto-focus function.

According to the first embodiment, the electronic image displayed on thecompact LCD 34 (FIG. 4) is projected onto the right image surface of theoperating-microscope optical system. If it is projected onto the leftimage surface instead of the right image surface, the same effect can beobtained.

Also, FIG. 6 shows that the electronic image appears at the peripheralportion in the upper-right quadrant of the observation field, it may belocated on any other quadrant. For instance, the electronic image may belocated, not limited to the upper-right quadrant, at a peripheralportion in the upper-left quadrant.

Also, the electronic image displayed on the compact LCD 34 (FIG. 4) isnot necessarily limited to that obtained from the endoscope. An imagederived from other image pickup optical system such as a video camera isapplicable, or there may be directly displayed an electronicallyproduced image such as a picture created by computer graphics or awaveform display obtained from a nerve monitor, which is indispensablyused in certain operations.

Also, the compact LCD 34 (FIG. 4) used in the first embodiment may bereplaced by other electronic image display means, such as a plasmadisplay.

Next, in reference to FIG. 7, the configuration of the binocular sectionused in the first embodiment, which employs Siedentoph system foradjustment of interpupillary distance, will be detailed. According toFIG. 7, the image projecting optical system is represented by thereference numeral 57, the movable section of the image projectingoptical system 57 by the reference numeral 58, the rotation axis of theparallelogram prism 1 by the reference numeral 60, the compact LCD bythe reference numeral 62, and the fixed section of the image projectingoptical system 57 by the reference numeral 63.

Of optical elements constituting the movable section 58, which moves inaccordance with adjustment of interpupillary distance of the binoculareyepiece, an optical element 59, which is the first element to receivethe beam emergent from the compact LCD 62, is disposed at a positionseparate from the rotation axis 60 of the parallelogram prism 1 by thedistance c=20 mm. Also, arrangement is made so that an optical axis 61of the eyepiece optical system 3 is separate from the rotation axis 60of the parallelogram prism 1 by the distance d=34.5 mm.

According to this configuration, shift amount of the optical element 59in accordance with the adjustment of interpupillary distance is smallerthan that of the image surface. Consequently, the fixed section 63 ofthe image projecting optical system 57, which is designed to forward thebeam from the compact LCD 62 to the movable section 58 as stationarypositioned during the adjustment of interpupillary distance, can be mademore compact. While arrangement is made so that c=20 mm according to thefirst embodiment, the distance “c” may be set at a value smaller than 20mm.

Furthermore, the image projecting optical system 9 and theoperating-microscopic optical system are provided independent of eachother, without any common constituent optical element until the imagesurface. Therefore, these optical systems do not degrade images formedby each other, and thus both the images can be viewed clearly.

Second Embodiment

In reference to FIGS. 8, 9 and 10, description will be made of anoptical arrangement around eyepiece optical systems and image projectingoptical systems according to the second embodiment of the presentinvention.

According to the second embodiment, a binocular housing not shown in thedrawings houses a binocular optical system (of the entireoperating-microscopic optical system) shown in FIG. 10 and, as shown inFIGS. 8 and 9, a pair of compact LCDs 67 for displaying thereonelectronic images and a pair of image projecting optical systems 69 forintroducing light emergent from the compact LCDs 67 into left and rightimage surfaces 68 included in the binocular optical system of the entireoperating-microscopic optical system.

According to the second embodiment, the binocular optical system of theentire operating-microscopic optical system employs Jentzsche system foradjusting interpupillary distance; as illustrated in FIG. 10, a pair ofmirrors 65 disposed directly before a pair of eyepiece optical systems64 slide in mutually opposite directions while the left and righteyepiece optical systems 64 slide in resultant directions of theirrespective horizontal components corresponding to the horizontalmovement of the mirrors 65 and a vertical component for compensation forchange of path length caused by the movement of the mirrors 65, so as tochange distance “e” between left and right eyepoints 66. Although notdescribed in detail here, the binocular optical system according to thesecond embodiment includes a pair of trapezoidal prisms P to reflectrays three times inside themselves, as shown in FIG. 10.

As shown in FIGS. 8 and 9, each of the image projecting optical systems69 includes a collimating optical system 70 for collimating a beam ofrays emergent from the LCD 67, a prism 72, an imaging optical system 73for forming an image onto the image surface 68 using a beam of parallelrays emergent from the collimating optical system 70, and a prism 74.The collimating optical system 70, the compact LCD 67, a mirror 71, andthe prism 72 constitute a fixed section, which remains stationary duringthe adjustment of interpupillary distance of the binocular eyepiece,while the imaging optical system 73 and prisms 74 and 75 constitute amovable section, which moves integral with the image surface 68 inaccordance with the adjustment of interpupillary distance of thebinocular eyepiece of the operating microscope.

The light beam travelling between the fixed section and the movablesection in the image projecting optical system 69 is constructed ofparallel rays. The prism 72 is located so that an optical axis 76 of theimaging optical system 73 aligned with a central axis of the beam ofparallel rays runs parallel to the slide direction of the image surface68, onto which the electronic image is projected. Also, the imagingoptical system 73 and the prism 74 in the movable section areconstructed to slide on the optical axis 76 integral with the imagesurface 68 in accordance with the adjustment of interpupillary distanceso that the entrance aperture of the movable section also slides asinserted in the optical axis 76. Therefore, even if the movable sectionslides in accordance with the adjustment of interpupillary distance ofthe binocular eyepiece of the operating microscope, the electronic imagefrom the compact LCD 67 can always be projected onto the image surface68. Accordingly, as shown in FIG. 8, the observer 50 can view theelectronic images from the compact LCDs 67 inside observation fieldsformed by the left and right eyepiece optical systems 64 of theoperating-microscopic optical system.

Next, the optical principle relating to the image projecting opticalsystem with the above-mentioned configuration of the second embodimentwill be described in reference to FIGS. 11A and 11B. According to FIGS.11A and 11B, the compact LCD is represented by the reference numeral 77,the beam of rays emergent from the compact LCD 77 by the referencenumeral 78, the fixed section of the image projecting optical system bythe reference numeral 79, the collimating optical system by thereference numeral 80, the beam of parallel rays by the reference numeral81, the movable section of the image projecting optical system by thereference numeral 82, the imaging optical system by the referencenumeral 83, the center axis of the beam of parallel rays 81 by thereference numeral 84, and the image surface provided for observation viaeyepiece by the reference numeral 85.

As shown in FIGS. 11A and 11B, since the beam of rays 78 emergent fromthe compact LCD 77 is transmitted through the collimating optical system80 to become the beam of parallel rays 81, the imaging optical system 83in the movable section can receive the beam from the compact LCD 77 in aconstant condition even if it slides along its own optical axis, whichis aligned to the central axis 84 of the beam of parallel rays 81. Also,since the image surface 85 slides integral with the imaging opticalsystem 83, the imaging optical system 83 constantly forms an imagederived from the electronic image at a predetermined position on theimage surface 85.

In the image projecting optical systems 69 used in the secondembodiment, prisms and mirrors are configured to reflect rays asillustrated in FIGS. 8 and 9. According to this configuration, even ifthe movable sections 82 (FIGS. 11A and 11B) of the image projectingoptical system moves in accordance with the adjustment of interpupillarydistance of the binocular eyepiece, the electronic images displayed onthe compact LCDs 67s are constantly projected in their proper attitudes(without rotation) onto predetermined portions 86 in the image surfaces68.

The operating microscope according to the second embodiment also is usedwith an endoscope 37 provided with CCD as shown in FIG. 5. The endoscope37 with a CCD cooperates with the operating microscope so as tofacilitate observation of a narrow cavity interior 36 located in parts51 under operation, which is not observable by the operating microscopealone. If an electronic image picked up by the endoscope 37 is displayedon the compact LCDs 67 of the image projecting optical systems 69 (FIGS.8 and 9), the electronic images displayed on the compact LCDs 67 alsoare projected onto the left and right image surfaces as to follow thesame, which are constructed to be movable for adjustment ofinterpupillary distance of the binocular section 48, and thereby anobserver 50 can observe an operating-microscopic image 39 and anendoscopic image 40 simultaneously within an observation field 38 formedby the right and left eyepiece optical systems 64 (FIGS. 8, 9 and 10).Also, if the endoscope 37 is constructed to allow three-dimensionalobservation, not only the operating-microscopic image 39 but also theendoscopic image 40 can be observed stereoscopically.

In addition, according to the second embodiment, since the compact LCDs67, the collimating optical systems 70, the mirrors 71 and the prisms72, which occupy a considerable space in a binocular housing, arefixedly positioned as shown in FIGS. 8 and 9, the housing is notrequired to provide an extra space for their movement and accordingly, acompact operating microscope with high operability is realized whileachieving the above-mentioned advantage, i.e. simultaneous observationof the operating-microscopic image and the endoscopic image.

Next, in reference to FIG. 12, description will be made of the imagesprovided for observation via left and right eyepieces of the operatingmicroscope according to the second embodiment. According to FIG. 12, theobservation fields formed by the eyepieces of the operating microscopeare represented by the reference numeral 87, the operating-microscopicimages by the reference numeral 90, and the endoscopic images by thereference numeral 91.

The image projecting optical systems 69 (FIGS. 8 and 9) of the secondembodiment project the electronic images displayed on the compact LCDs67 (FIGS. 8 and 9) onto the left and right image surfaces 68 (FIGS. 8and 9) so that the endoscopic images 91 are located at peripheralportions 88 in the upper-right quadrants of the observation fields 87.As a result, the vicinities of field centers 89 of the observationfields 87 of the microscope are reserved for the operating-microscopicimages 90.

According to this configuration, observation of theoperating-microscopic images 90, which are the principal, is compatiblewith observation of the endoscopic images 91, which serve as theauxiliary, and in addition, the observer can integrate visualinformation via the left and right eyes not only with respect to theoperating-microscopic image 90 but also to the endoscopic image 91. Onthe other hand, since an object located in the vicinity of the fieldcenter 89 is used as a target to be in focus by an auto-focusing device,it is necessary in using a microscope with auto-focusing function thatthe vicinity of the field center 89 is occupied by theoperating-microscopic image. The image arrangement in the observationfield according to the second embodiment is preferable also in that itwould not affect auto-focus function.

According to the second embodiment, the electronic images displayed onthe compact LCDs 67 (FIGS. 8 and 9) are projected onto the left andright image surfaces of the operating-microscopic optical system. Theconfiguration may be modified so that only one of the image surfacesreceives the electronic image.

Also, the electronic images displayed on the compact LCDs 67 (FIGS. 8and 9) are not necessarily limited to those obtained from the endoscope.Images derived from other image pickup optical system such as a videocamera are applicable, or there may be directly displayed electronicallyproduced images such as pictures created by computer graphics orwaveform displays obtained from a nerve monitor, which is indispensablyused in certain operations.

Also, the compact LCDs (FIGS. 8 and 9) used in the first embodiment maybe replaced by other electronic image display means, such as plasmadisplays.

Furthermore, the image projecting optical systems 69 (FIG. 8 and 9) andthe operating-microscopic optical system of the second embodiment areprovided independent of each other, without any common constituentoptical element until the image surfaces. Therefore, these opticalsystems do not degrade images formed by each other, and thus both theimages can be viewed clearly.

The following is numerical data of an image projecting optical systemapplied to the first and second embodiments. Also, FIG. 13 illustratesthis image projecting optical system in detail.

object point   d₀ = 36.5711 r₁ = 85.0398   d₁ = 2.1 n₁ = 1.76182 ν₁=26.52 r₂ = 29.4024   d₂ = 4.5 n_(2 = 1.54633) ν₂ =64.14 r₃ = −40.1071  d₃ = 2.0 r₄ = 492.0841   d₄ = 2.5 n₄ = 1.51742 ν₄ = 52.43 r₅ =−51.2531   d₅ = 15.0 r₆ = ∞   d₆ = 12.0 n₆ = 1.56883 ν₆ = 56.36 r₇ = ∞  d₇ = 6˜21.5536 r₈ = ∞   d₈ = 11.0 n₈ = 1.56883 ν₈ = 56.36 r₉ = ∞   d₉= 2.4 r₁₀ = 14.2721   d₁₀ = 4.0 n₁₀ = 1.51742 ν₁₀ = 52.43 r₁₁ = −8.0096  d₁₁ = 1.1 n₁₁ = 1.76182 ν₁₁ = 26.52 r₁₂ = −16.5120   d₁₂ = 8.5 r₁₃ = ∞  d₁₃ = 14.0 n₁₃ = 1.56883 ν₁₃ = 56.36 r₁₄ = ∞   d₁₄ = 0.5 image point

Also, the following is numerical data of an image projecting opticalsystem (compatible with high-image-quality LCD) applied to the first andsecond embodiments. Also, FIG. 14 illustrates this image projectingoptical system in detail.

object point   d₀ = 36.5 r₁ = 112.1074   d₁ = 2.8 n₁ = 1.81600 ν₁ =46.62 r₂ = −112.1074   d₂ = 3.1 r₃ = −129.102   d₃ = 2.2 n₃ = 1.84666 ν₃= 23.78 r₄ = 129.102   d₄ = 3.1 r₅ = 72.0703   d₅ = 3.2 n₅ = 1.81600 ν₅= 46.62 r₆ = −72.0703 d₆ = 36.5˜52.05635 r₇ = 39.0847   d₇ = 2.2 n₇ =1.88300 ν₇ = 40.76 r₈ = −19.1041   d₈ = 1.2 r₉ = −12.4648   d₉ = 1.2 n₉= 1.72151 ν₉ = 29.23 r₁₀ = 12.4648   d₁₀ = 1.2 r₁₁ = 15.7439   d₁₁ = 2.7n₁₁ = 1.88300 ν₁₁ = 40.76 r₁₂ = −25.2987   d₁₂ = 8.97 r₁₃ = ∞   d₁₃ =14.0 n₁₃ = 1.56883 ν₁₃ = 56.36 r₁₄ = ∞   d₁ = 0.7667 image point

Third Embodiment

In reference to FIG. 15, description will be made of the thirdembodiment, according to which a light intercepting member is disposedin the moving section of such an image projecting optical system as usedin the first or second embodiment. In FIG. 15, the reference numeral 92represents a light intercepting member, the reference numeral 93represents an image surface provided for observation via eyepiece, thereference numeral 94 represents an eyepiece optical system, thereference numeral 95 represents a pupil of the observer, and the symbolο represents an imaging point.

According to the third embodiment, a light intercepting member 92 isarranged in the movable section 26 (FIG. 3), 82 (FIGS. 11A and 11B),which is moved in accordance with adjustment of interpupillary distanceof the binocular section 48 (FIG. 5), of the image projecting opticalsystem 9 (FIG. 1), 69 (FIGS. 8 and 9) of the first and secondembodiment, to intercept a part of the light beam used to form theoperating-microscopic image 90 (FIG. 12), i.e. to cause a partialeclipse in the operating-microscopic image 90. The third embodimentarranges the image projecting optical system 9, 69 in such a manner thatthe electronic image displayed on the compact LCD 34 (FIG. 4), 67 (FIG.8) is projected at a position in this eclipsed portion of theoperating-microscopic image 90. As shown in FIG. 15, the lightintercepting member 92 serves as a reflecting member also for reflectingthe beam emergent from the compact LCD, to save a space inside thebinocular housing 5 (FIG. 1). According to the above-describedconfiguration, since the operating-microscopic image 55 (FIG. 6) and theendoscopic image 56 (FIG. 6) do not overlap with each other, theobserver can observe both the images simultaneously and clearly.

If the compact LCD 34 is provided with an image other than theendoscopic image, for example, a waveform display of the nerve monitoror the like, the light intercepting member 92 may be replaced by a halfmirror, because such an image can be satisfactorily observed even ifoverlapping with the operating-microscopic image.

Fourth Embodiment

In reference to FIG. 16, description will be made of the fourthembodiment, according to which a movable prism is disposed in themovable section of such an image projecting optical system as used inthe first or second embodiment. In FIG. 16, the reference numeral 97represents a movable prism, and the reference numeral 98 represents themovable prism after movement.

According to the fourth embodiment, a movable prism 97 that isconstructed to be movable at observer's will is arranged in the movablesection 26 (FIG. 3), 82 (FIGS. 11A and 11B), which is moved inaccordance with the adjustment of interpupillary distance of thebinocular section 48 (FIG. 5), of the image projecting optical system 9(FIG. 1), 69 (FIGS. 11A and 11B) of the first and second embodiment, sothat the observer has an option to shift the endoscopic image 91 (seeFIG. 12) out of the observation field by displacing the movable prism97. According to this configuration, if the observer judges theendoscopic image unnecessary, it can be removed from the observationfield.

Fifth Embodiment

According to the fifth embodiment, as shown in FIG. 17, a binocular unit99 incorporating therein a binocular optical system 6 inclusive of apair of left and right eyepiece optical systems 18, an image projectingoptical system, and a compact LCD 7, which are all shown in FIG. 1, isconstructed to achieve removable mount on a main unit 100 of theoperating microscope.

According to this configuration, the binocular unit 99 is modularlyreplaceable with a normal type binocular unit 101 of the operatingmicroscope. Consequently, an observer who does not need simultaneousobservation of the operating-microscopic image 39 (FIG. 5) and theendoscopic image 38 (FIG. 5) can observe the operating-microscopic imagealone using the normal type binocular unit 101. In a medical facility,one operating microscope is often used in common among, for instance,cerebral neurosurgery, ophthalmology and orthopedics but in differentapplication modes. Modular replacement of the binocular units realizesan operating microscope that meets various requirements which differ byclinical specialty.

Sixth Embodiment

FIG. 18 is directed to the sixth embodiment of the present invention.According to the sixth embodiment, a movable housing 104 and a fixedhousing 105 constitute a binocular section of the operating microscope,which is an analogue of the binocular section 48 shown in FIG. 5, sothat the binocular section has variable inclination angle. Furthermore,the image projecting optical system 9 (FIG. 1) is housed in the movablehousing 104. According to this configuration, when the image surfacesprovided for observation via eyepiece shift in accordance with change ofinclination angle, the image projecting optical 9 moves integral withthe image surfaces, without changing its position relative to the imagesurfaces. Hence, it is not necessary to provide an additional mechanismto make the image projecting optical system 9 follow the movement of theimage surfaces. The sixth embodiment thus can prevent extra bulkiness ofthe operating microscope.

Seventh Embodiment

FIG. 19 is directed to the seventh embodiment of the present invention.According to the seventh embodiment, the compact LCD 7 (FIG. 1) and theimage projecting optical system 9 (FIG. 1) are housed in a housing 106to form an image projecting unit 107. Furthermore, the image projectingunit 107 is constructed to be removably mounted on a binocular housing108 that houses an ordinary binocular optical system.

The seventh embodiment achieves the same effect as obtained by the fifthembodiment only with engagement and disengagement of the imageprojecting optical unit 107; replacement of the binocular housing 108 isnot needed.

Eighth embodiment

FIGS. 20A, 20B, 21A, 21B are directed to the eighth embodiment of thepresent invention.

According to the eighth embodiment, a pair of left and right trapezoidalprisms P are so arranged in a binocular optical system 6 (FIG. 1) of theoperating microscope used in the first or second embodiment as toreflect rays three-times inside themselves. In the operating microscopeaccording to the present invention, it is necessary to secure a space toaccommodate the image projecting optical system 9 (FIG. 1) inside oradjacent to the binocular housing 5 (FIG. 1). Therefore, opticalcomponents constituting the binocular optical system 6 (FIG. 1) arerequired to be small as much as possible. This requirement is moreurgent with respect to prisms, which occupy relatively large space,specifically with respect to a trapezoidal prism Q (FIG. 22A), which isarranged to reflect rays twice inside itself to turn the travellingdirection of the rays by 180°. According to the eighth embodiment, thetrapezoidal prism Q for two-times reflection is replaced by atrapezoidal prism P (FIG. 22B) so as to reduce the size of the binocularoptical system 6 in the direction of prism thickness. Consequently, acompact and highly operable binocular section provided with imageprojecting function is realized.

Also, if an ordinary binocular section of an operating microscopeemploys the above-mentioned prism configuration of the eighthembodiment, it also can reduce its size.

The following is numerical data of the binocular optical section shownin FIGS. 20A and 20B provided with Siedentoph system for adjustment ofinterpupillary distance.

r₁ = 36.53   d₁ = 1.9 n₁ = 1.60342 ν₁ = 38.03 r₂ = ∞   d₂ = 5.1 r₃ =75.245   d₃ = 2.4 n₃ = 1.51633 ν₃ = 64.14 r₄ = −30.385   d₁ = 1.6 n₄ =1.58144 ν₄ = 40.75 r₅ = 30.385   d₅ = 22.5 r₆ = ∞   d₆ = 25.607 n₆ =1.56883 ν₆ = 56.36 r₇ = ∞   d₇ = 1.132 r₈ = ∞   d₈ = 45.244 n₈ = 1.56883ν₈ = 56.36 r₉ = ∞   d₉ = 8.0 r₁₀ = ∞   d₁₀ = 55.426 n₁₀ = 1.51633 ν₁₀ =64.14 r₁₁ = ∞   d₁₁ = 1.0 r₁₂ = ∞   d₁₂ = 22.0 n₁₂ = 1.56883 ν₁₂ = 56.36r₁₃ = ∞   d₁₃ = 7.931 r₁₄ = ∞   d₁₄ = 58.5 n₁₄ = 1.56883 ν₁₄ = 56.36 r₁₅= ∞   d₁₅ = 3.53 O (image point)

Also, the following is numerical data of the binocular optical sectionshown in FIGS. 21A and 21B provided with Jentzsche system for adjustmentof interpupillary distance.

r₁ = 35.1815   d₁ = 2.4 n₁ = 1.51742 ν₁ = 52.43 r₂ = −24.3244   d₂ = 1.6n₂ = 1.62588 ν₁ = 35.70 r₃ = −76.5057   d₃ = 9.5 r₄ = 1840.6599   d₄ =1.6 n₄ = 1.51633 ν₄ = 64.14 r₅ = 29.1137   d₅ = 11.5 r₆ = ∞   d₆ =25.607 n₆ = 1.56883 ν₆ = 56.36 r₇ = ∞   d₇ = 1.132 r₈ = ∞   d₈ = 45.239n₈ = 1.56883 ν₈ = 56.36 r₉ = ∞   d₉ = 8.0 r₁₀ = ∞   d₁₀ = 71.014 n₁₀ =1.56883 ν₁₀ = 56.36 r₁₁ = ∞   d₁₁ = 10.0 r₁₂ = ∞   d₁₂ = 24.0 n₁₂ =1.56883 ν₁₂ = 56.36 r₁₃ = ∞   d₁₃ = 15.1032 O (image point)

In the numerical data of the embodiments mentioned above, r₁, r₂, . . .represent radii of curvature of individual lens or prism surfaces; d₁,d₂, . . . thicknesses of individual lenses or prisms, or spacestherebetween; n₁, n₂,. . . refractive indices of individual lenses orprisms; v₁, v₂, . . . Abbe's numbers of individual lenses or prisms.

Ninth Embodiment

FIG. 23 is directed to the ninth embodiment of the present invention. InFIG. 23, the reference numeral 109 represents an eyepiece opticalsystem, the reference numeral 110 represents an exit pupil of theoperating-microscopic optical system, the reference numeral 111represents an exit pupil of the image projecting optical system, thereference numeral 112 represents an eyepoint of the operatingmicroscope, the reference numeral 113 represents anoperating-microscopic image, and the reference numeral 114 represents anelectronic image as projected from the compact LCD 7.

According to the ninth embodiment, the operating microscope similar tothat of the first or second embodiment is arranged so that the exitpupil 111 of the image projecting optical system 9 (FIG. 1) is formedvia the eyepiece optical system 109 at the same position as the exitpupil 110 of the operating-microscopic optical system but to have thediameter of 3 mm, which is larger than that of the exit pupil 110 of theoperating-microscopic optical system.

According to this pupil arrangement, when an observer sets the eye atthe eyepoint 112 of the operating microscope, the electronic image 114as projected onto the image surface of the operating-microscopic opticalsystem and the operating-microscopic image 113 are simultaneouslyobservable.

In general, the operating-microscopic image 113 has a higher luminancethan that of the electronic image 114 on the image surface, and thus theobserver often feels that the electronic image is darker than theoperating-microscopic image. According to the ninth embodiment, however,apparent difference in brightness is not so distinctive, becausediameter of the exit pupil 111 of the image projecting optical system 9is set to 3 mm so as to be larger than not only that of the exit pupil110 of the operating microscopic optical system but also the human pupildiameter of 2.5 mm.

Tenth Embodiment

In reference to FIGS. 24A and 24B, description will be made of the tenthembodiment of the present invention. In FIGS. 24A and 24B, the referencenumeral 115 represents a compact LCD, the reference numeral 116represents a display surface of the compact LCD 115, the referencenumeral 117 represents an entrance pupil of the image projecting opticalsystem 9 (FIG. 1), the reference numeral 118 represents an endoscopicimage displayed on the display surface 116, the reference numeral 119represents the center point of the endoscopic image 118, the referencenumeral 120 represents the periphery of the endoscopic image 118, thereference numeral 121 represents a beam of rays emergent from thedisplay surface 116 of the compact LCD 115 and incident on the imageprojecting optical system 9, the reference numeral 122 represents aprincipal ray of the beam 121, and the reference numeral 123 representsa collimating optical system of the image projecting optical system 9.

According to the tenth embodiment, the image projecting optical system 9similar to that of the first or second embodiment is constructed so thatthe endoscopic image 118 displayed on the display surface 116 of thecompact LCD 115 has a circular contour with diameter of 16.8 mm, and theposition of the entrance pupil 117 of the image projecting opticalsystem 9 is determined to be distant from the display surface 116 of thecompact LCD 115 at least by 68.5 mm.

This arrangement is based on the condition:

A≧(H/tan 7°)

where A is a distance from the display surface 116 of the compact LCD115 to the entrance pupil of the image projecting optical system 9, andH is a distance from the center point 119 to the periphery 120 of theendoscopic image 118 on the display surface 116. In the case of thetenth embodiment, A=100 and H=8.4, and thus the above numericalcondition is satisfied.

When this numerical condition is satisfied, the principal ray 122 of thebeam 121 to be incident on the image projecting optical system is not sooblique with respect to the display surface 116 of the compact LCD 115.Therefore, even if the compact LCD 115 does not have excellent angularrange characteristic in color tone reproducibility, the entire image canbe observed in good color tone condition.

Eleventh Embodiment

In reference to FIGS. 25A and 25B, description will be made of theeleventh embodiment of the present invention. As shown in FIGS. 25A and25B, according to the eleventh embodiment, a binocular housing 124 isprovided with a space for accommodating a pair of compact LCDs 127 and apair of image projecting optical systems 128 at a position to face theforehead 125 of an observer who looks into the binocular eyepiece.

According to this arrangement, the binocular housing 124 presents itsbulkiness necessitated by the built-in LCD 127s and the image projectingoptical systems 128 only in the upward direction, free from any otherprojecting portions in the downward direction to approach the observer'shands or in the lateral directions. Consequently, the binocular housing124 would not be the obstruct to the operation and thus loss of workefficiency is obviated.

The above-described first to eleventh embodiments are also applicable tothose stereomicroscopes used for purposes other than surgical operation,to attain the same effects as described above.

Twelfth embodiment

FIG. 26 is directed to the twelfth embodiment of the present invention.The operating microscope according to the twelfth embodiment comprisesan image projecting optical system for introducing an image derived froman endoscopic optical system, which is provided separate from anoperating-microscopic optical system, into an eyepiece optical system ofthe operating microscope so that the operating-microscopic image and theendoscopic image can be simultaneously observed. As shown in FIG. 26, abeam of rays 132 emergent from the endoscopic image 131 is convertedinto a beam of divergent rays 134 via a first lens unit 133 a of animage projecting optical system 133. A second lens unit 133 b of theimage projecting optical system 133 receives the beam of divergent rays134 to form an image while moving in a direction of an optical axis Mintegral with an eyepiece optical system 136 in accordance withadjustment of interpupillary distance. An imaging position 137 by theimage projecting optical system 133 is shifted from an image surface135, which is predetermined for observation via eyepiece, in accordancewith the adjustment of interpupillary distance. However, since the shiftof the imaging position occurs within a range W of focal depth of anobserver's eye 138, the observer can observe the operating-microscopicimage 140 and the endoscopic image 141 on the image surface 135simultaneously and clearly also. In the twelfth embodiment, the beam ofrays emergent from the first lens unit 133 a of the image projectingoptical system 133 is designed to be divergent. However, the arrangementmay be modified so that the beam of rays is convergent.

In the operating microscope according to the twelfth embodiment, a partof the image projecting optical system 133 is movable within a range asallows an entrance aperture thereof to receive a beam of rays, and adefocus amount of the projected image in reference to the image surface135 provided for observation via eyepiece, which amount varies with themovement of the part of the image projecting optical system 133,satisfies the following condition:

−2((foc(mm))²/1000(mm))<X(mm)<2((foc(mm))²/1000(mm))

where foc is a focal length of the eyepiece optical system, and X is thedefocus amount.

The above condition is set considering focal depth of the observerseyes. If the condition is exceeded, the endoscopic image appears to beout of focus, whereas the operating-microscopic image can be observed ingood focus; simultaneous observation of both the images in good focuscondition cannot be realized. In contrast, according to the twelfthembodiment, even if the projected image is defocused in reference to theimage surface provided for observation via eyepiece in accordance withmovement of the part of the image projecting optical system, the defocusamount falls within a range of focal depth of the observer' eyes.Therefore, the operating-microscopic image and the endoscopic image arecompatible for observation in the operating microscope.

Thirteenth Embodiment

In reference to FIGS. 27A and 27B, description will be made of thethirteenth embodiment of the present invention. According to thethirteenth embodiment, as schematically shown in FIG. 27A, not only animage from an endoscope 37 but also images from a waveform monitor 146,CT 147 etc. are fed to an image processor unit 145 so as to besimultaneously displayed on a single display surface of a compact LCD148 shown in FIG. 27B. The reference numerals shown in FIG 27A but notspecifically referred to here represent the same devices or elements asrepresented by the same reference numerals shown in FIG. 5. As shown inFIG. 27B, these plurality of images displayed on the compact LCD 148 areprojected by an image projecting optical system 149 onto an imagesurface 151 included in an operating-microscopic optical system 150 forobservation via eyepiece. Consequently, an observer 50 can obtain usefulvisual information to facilitate the operation such as an endoscopicimage 155, a waveform display 156, a CT image 157 etc. along with anoperating-microscopic image 152 by observing the images within oneobservation field 38 as enlarged by an eyepiece optical system 153.

Furthermore, since a plurality of images are displayed on one displaysurface, to dispense with additional compact LCDs or image projectingoptical systems, bulkiness of the housing is avoided and accordingly acompact and highly operable operating microscope can be realized. In thecase, although individual images on the display surface are rendered tobe small, the observer is able to observe them without difficulty byselecting magnification of the image projecting optical systemappropriately. For the compact LCD 148 to display a plurality of images,that having much oblong display surface with aspect ratio of 16:9 ispreferable.

Fourteenth Embodiment

FIG. 28 is directed to the fourteenth embodiment of the presentinvention. An image processor unit 160 according to the fourteenthembodiment is connected with an endoscope 37 (via a camera control unit41 and a CCD camera adapter for endoscopes 43) and a waveform monitor146 in the same manner as shown in FIG. 27A, and controls a compact LCD161 so that an endoscopic image 155 and a waveform display 156 aresimultaneously displayed side by side on the display surface of thecompact LCD 161. These plurality of images displayed on the compact LCD161 are projected by an image projecting optical system 162 onto animage surface 163 included in an operating-microscopic optical system150 for observation via eyepiece. Furthermore, of optical membersincluded in the image projecting optical system, a mostimage-surface-side reflecting mirror 165 is divided into a half mirror165 a and a full mirror 165 b arranged side by side. The former isdesigned to reflect a beam of rays emergent from the waveform display156 and the latter is designed to reflect a beam of rays emergent fromthe endoscopic image 155.

According to the above-described configuration of the fourteenthembodiment, an observer can obtain useful visual information tofacilitate the operation such as the endoscopic image 155, the waveformdisplay 156 etc. along with an operating-microscopic image 164 byobserving the images within one observation field as enlarged by aneyepiece optical system 153. Furthermore, since a plurality of imagesare displayed on one display surface, to dispense additional compactLCDs or image projecting optical systems, bulkiness of the housing isavoided and accordingly a compact and highly operable operatingmicroscope can be realized. For the compact LCD 161 to display aplurality of images, that having much oblong display surface with aspectratio of 16:9 is preferable.

Also, according to the configuration of the fourteenth embodiment, sincethe endoscopic image 155 is projected onto the image surface 163 afterbeing reflected by a mirror or a full reflection prism that is insertedin a beam of rays travelling through the operating-microscopic opticalsystem 150, a portion of the operating-microscopic image 164 locatedcorresponding to the endoscopic image 155 is intercepted by the mirroror the prism and thus is not visible to the observer. Consequently, theoperating-microscopic image 164 does not overlap with the endoscopicimage 155 on the image surface 163. This arrangement is made consideringthat both the operating-microscopic image 164 and the endoscopic image155 carry fine and complicated visual information and thus are likely tospoil each other in overlapping. According to the fourteenth embodiment,the operating-microscopic image 164 and the endoscopic image 155 aredistinctively observed under the non-overlap condition. In addition,both the images are free from loss of brightness caused by overlapping,and thus individual bright images can be observed.

On the other hand, the waveform display 156 or a text is rather simpleas visual information. Therefore, even if such an image is made tooverlap with the operating microscopic image 164, individual images areeasily recognizable. Considering this fact, according to the fourteenthembodiment, the waveform display 156 is made to overlap with theoperating-microscopic image 164 on the image surface 163 using the halfmirror 165. In this arrangement, the waveform display 156 or the textleaves a large area in the observation field to be used for theoperating-microscopic image 164 because no portion of theoperating-microscopic image 164 is shaded for the purpose of observationof the waveform display 156 or the like, and thus does not impedeobservation of the operating-microscopic image 164, which is given ahigher priority in the operation. Furthermore, by adjusting intensityusing the image processor unit 160, the overlapping image such as thewaveform display 156 or the text can be highlighted or, for observingthe operating-microscopic image 164 alone, erased as required.

I claim:
 1. An operating microscope comprising: an eyepiece optical system constructed to be movable for adjustment of interpupillary distance; and an image projecting optical system for introducing an electronic image into said eyepiece optical system so that an operating-microscopic image and said electronic image are simultaneously observed, wherein a part of said image projecting optical system is constructed to be movable in such a range as allows an entrance aperture thereof to receive a beam of rays from said electronic image so that the beam of rays is always introduced into said eyepiece optical system, which is movable for adjustment of interpupillary distance.
 2. An operating microscope according to claim 1, wherein a defocus amount of an image projected by said projecting optical system in reference to an image surface provided for observation via said eyepiece optical system, which defocus amount varies with a movement of said part of said image projecting optical system, satisfies the condition: 2((foc(mm))²/1000(mm))<X(mm)<2((foc(mm))²/1000(mm)) where foc is a focal length of said eyepiece optical system, and X is the defocus amount.
 3. An operating microscope comprising: an eyepiece optical system; and an image projecting optical system for projecting an image derived from an endoscopic optical system, which is provided separate from an operating-microscopic optical system, into said eyepiece optical system so that an image from said operating-microscopic optical system and the image from said endoscopic optical system are simultaneously observed, wherein a part of said image projecting optical system is constructed to be movable in such a range as allows an entrance aperture thereof to receive a beam of rays; and wherein a defocus amount of the projected image in reference to an image surface provided for observation via said eyepiece optical system, which defocus amount varies with a movement of said part of said image projecting optical system, satisfies the condition: −2((foc(mm))²/1000(mm))<X(mm)<2((foc(mm)²/1000(mm)) where foc is a focal length of said eyepiece optical system, and X is the defocus amount. 